Antisense refers to a nucleic acid molecule that is complementary to an expressed messenger RNA sequence present in an organism. We are evaluating the use of various forms of antisense molecules, both catalytic (ribozymes) and noncatalytic in nature, to evaluate the function of specifi gene expression in the eye. Ribozymes complementary to interphotoreceptor retinoid-binding protein mRNA have been evaluated in vitro and in vivo. Antisense to aldose reductase is currently being evaluated in vivo.